Disclaimer: This tutorial is exclusively for Nexus 7 (2012), Nexus 4 and Nexus 7 (2013), if you do it on any other device you may brick it. Carefully follow the instructions given below.veroxybd.com
Things to Do
Installing the app is quiet easy, just go to MultiROM Manager to the Play store and then select MultiROM, recovery and kernel on the Install screen and tap Install (Your current ROM will not be affected).
To add a secondary custom ROM (Android)
You can visit the official XDA threads below for more information on this topic.
If you face any problem, ask in the official columns or in the comments section here.